JP2002035605A - Method of producing catalyst for purifying gap containing organic chlorinated compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a catalyst for purifying an waste gas containing organic chlorinated compounds, by which a component of the catalyst can be uniformly dispersed on the surface of each titanium oxide particle being a catalyst carrier. SOLUTION: In the method of producing the catalyst for purifying the gas containing organic chlorinated compounds, in which a catalytically active component is loaded on titanium oxide particles, the catalytically active component is loaded in the presence of a silane coupling agent containing an amino group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for purifying exhaust gas containing organic chlorinated compounds, and more particularly to a method for purifying exhaust gas suitable for removing harmful organic chlorinated compounds such as dioxin from exhaust gas.

[0002]

2. Description of the Related Art Conventionally, in the case of a catalyst in which a catalyst component is supported on a carrier mainly composed of titanium oxide, the surface of titanium oxide particles as a carrier is subjected to a coprecipitation method or an impregnation method using oxalic acid chelate. The catalyst component was supported.

[0003]

However, in these methods, the dispersion of the catalyst component on the particle surface is poor, and in order to exhibit high catalytic performance, it is necessary to disperse the catalyst component in fine particles uniformly on the surface of the catalyst carrier. There is. In addition, the size of the area (specific surface area) in contact with the outside air is also a large factor that determines the catalytic performance. However, the conventional titanium oxide particles have a specific surface area of about 60 to 80 m ² / g in the raw material powder for the catalyst carrier, There is a limit to increasing the specific surface area using titanium oxide particles.

An object of the present invention is to make it possible to highly disperse a catalyst component on the surface of titanium oxide particles as a carrier.
An object of the present invention is to provide a method for producing an exhaust gas purifying catalyst containing an organic chlorinated compound.

[0005]

Means for Solving the Problems To achieve the above object, the invention claimed in the present application is as follows. (1) A method for producing a catalyst for purifying an organic chlorinated compound-containing gas, in which a catalytically active component is supported on titanium oxide particles, characterized in that an amino group-containing silane coupling agent is coexistent when the catalytically active component is supported. A method for producing a catalyst for purifying a gas containing an organic chlorinated compound. (2) The method according to (1), wherein a titanium ion is present in addition to the silane coupling agent. (3) The method according to (1) or (2), wherein one or more particles selected from alumina, silica, and a composite oxide thereof are used in addition to the titanium oxide particles.

(4) The obtained catalyst has at least three peaks in the pore size distribution, and the first peak has a peak of 300 nm to 45 nm.
The method according to any one of (1) to (3), wherein the range of 0 nm, the second peak is in the range of 50 nm to 100 nm, and the third peak is in the range of 30 nm or less. (5) Titania particles having a particle diameter of 5 nm to 600 nm are prepared as a titania raw material, and a thermally decomposable substance having a particle diameter equal to or larger than a target pore diameter of the catalyst is kneaded as a porosifying agent,
Calcination to form the first peak of the pore size distribution, pores of other pore sizes to be formed as gaps between the titania particles, and amino group-containing silane coupling at any stage during the preparation of the catalyst. A method for producing a gas purification catalyst containing an organic chlorinated compound, characterized by adding a catalytically active component in the coexistence of an agent.

In the present invention, the amino group-containing silane coupling agent added when the catalyst component is supported refers to an amino group-containing silane coupling agent, and includes, for example, (1) N-2- (aminoethyl ) -3-Aminopropylmethyldimethoxysilane (or N-β (aminoethyl)
(2) N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, (3) N-2- (aminoethyl) -3-aminopropyltriethoxysilane , (4)
Examples thereof include 3-aminopropyltrimethoxysilane, (5) 3-aminopropyltriethoxysilane, and (6) N-phenyl-3-aminopropyltrimethoxysilane. Of these, the compounds (1), (2) and (3) are particularly preferably used.

[0008]

The amino group-containing silane coupling agent is adsorbed on the titanium oxide particles, and the ions of the catalyst component are trapped via the silane coupling agent. It can be carried. Incidentally, at the time of catalyst molding, a silane coupling agent may be used to improve the viscosity of the catalyst composition, but these are non-amino silane coupling agents,
It has little to do with the high dispersion of the catalyst components.

When titanium ions are allowed to coexist with the amino-based silane coupling agent, there is an effect of increasing the specific surface area. When alumina, silica, etc. are used, the titania and the catalyst component are supported on a carrier having a large specific surface area as compared with titania, such as alumina, silica, etc., so that the activity is at least as high as that of a conventional catalyst. Holding
Further, a catalyst having a larger specific surface area can be obtained.

The catalyst may be produced by a known method except that an amino group-containing silane coupling agent is co-present when the catalytically active component is supported. The amount of the silane coupling agent added during the production of the catalyst is 20 to 80% by weight in the catalyst raw material composition,
Particularly, 25 to 40% by weight is preferable. The particle diameter of the titanium oxide particles used in the present invention is preferably in the range of 5 nm to 600 nm.

The catalyst produced according to the present invention has at least three peaks in the pore size distribution of the catalyst in order to reduce the diffusion resistance of molecules of the order of dioxins in the pores and improve the catalytic performance. , The first peak is 300n
m to 450 nm, preferably 350 nm to 450 nm
(More preferably, 380 nm to 420 nm),
The second peak is between 50 nm and 100 nm, preferably 75 nm
nm to 100 nm (more preferably, 90 nm to 100 nm).
nm) and the third peak preferably has a range of 30 nm or less, preferably 20 nm or less.
The pore size distribution of the catalyst in the present invention is a value measured by a mercury porosimetry and read from a differential pore volume distribution diagram.

The first peak catalyst pore size distribution has the effect of reducing the diffusion resistance of dioxins inside the catalyst, and the second peak catalyst pore size distribution coexists with the first peak. It has the function of inducing dioxins approaching via the pore size of the first peak to the pore size distribution of the third peak. The pore size distribution of the third peak coexists with the first and second peaks and the first peak. And acts to finally capture dioxins not captured by the pore size distribution of the second peak.

In the catalyst of the present invention, it is desirable that the carrier is titanium oxide and the catalytically active component is vanadium oxide and / or tungsten oxide. Furthermore, vanadium oxide of the active component is 0.1% of the total weight of the catalyst. 01
% To 30% by weight, preferably 1% to 5% by weight.
01% to 30% by weight, preferably 10% to 20% by weight
% By weight. If it exceeds this range, sufficient catalytic performance cannot be obtained. Further, the specific surface area of the catalyst is 5
It is preferably at least 0 m ² / g, preferably at least 75 m ² / g, more preferably at least 100 m ² / g.
When the specific surface area is less than this range, the catalytic performance per unit volume is not sufficient and is not practical.

As a method for producing the catalyst having the above-mentioned specific pore size distribution, the following method is preferably used. That is,
One or more titania particles having a particle size of 5 nm to 600 nm as the titania raw material (in this case, the titania particles are primary particles composed of a single crystal or a dense polycrystalline particle, or substantially primary particles). Together with a catalytically active component (vanadium oxide and / or tungsten oxide), a porogen (for example, a thermally decomposable compound having a particle size of 50 to 1000 nm) and a silane coupling agent. A method of kneading, molding, and firing, the particle size being 5 nm to 600 n as described above.
m titania particles having one or more particle diameters (in this case, the titania particles are primary particles composed of single crystal or dense polycrystalline particles, or substantially composed of primary particles) Secondary particles) as a carrier material, kneading, molding and calcining together with a porogen (for example, a thermally decomposable compound having a particle size of 50 nm to 1000 nm) and a silane coupling agent, and then carrying a catalytically active component by an impregnation method. There is a firing method. The active ingredient may be supported by a coprecipitation method or the like at the time of producing the titania particles. The particle size of the raw titania particles is 5 nm to 600 nm
, Preferably 50 nm to 400 nm, more preferably 100 nm to 200 nm. Outside this range, it is difficult to form pores corresponding to the second peak or pores corresponding to the third peak.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the process for producing a catalyst according to the present invention, the porogen is a calcination temperature or lower (about 400 ° C. to 80
(0 ° C.), for example, a material which is easily thermally decomposed, such as methacrylic resin, acrylic resin, acetal resin, and phenol resin. The particle size of the porous agent is larger than the pore size to be produced. For example, 40
In the case of opening pores of 0 nm, a porogen having a particle diameter of 400 nm or more is used. The rough guide is about 1.2 to 1.5 times the pore diameter to be produced, but this value is determined in consideration of the physical properties (depending on the type of the above-mentioned resin) of the porogen.

The second and third peaks have a particle diameter of 5n.
m-600 nm titania particles (in this case, the titania particles are primary particles composed of single crystals or dense polycrystalline grains, or secondary particles substantially composed of primary particles). The gap can be formed by controlling the packing density.

In addition, the second peak of 50 nm to 1 nm
In order to obtain a peak in the range of 00 nm, for example, secondary particles having a particle size of 5 nm to 600 nm may be used as the raw material titania, and the secondary particles may be kneaded and fired. The size of the secondary particles can be controlled by the temperature, pH, and use of a surfactant during the preparation. Further, it can also be controlled by performing a high dispersion treatment with a sand mill. Further, a third peak of 30 nm or less can be formed as a gap between the primary particles of titania. The gap between the primary particles can be formed by appropriately selecting the particle size of the primary particles themselves and the production condition of the secondary particles so as to obtain a target pore size.

Since the pores of the catalyst are formed during the production of the titania carrier, the catalyst active component is supported by a kneading method,
Either the impregnation method or the coprecipitation method may be used. In the case of the kneading method or the like, the active component is supported at the same time as the carrier preparation (pore formation), and in the case of the impregnation method or the like, the active component is supported after the carrier preparation (after pore preparation). . In the case of the coprecipitation method, the active ingredient is supported on the titania raw material before the preparation of the carrier (before the preparation of the pores).

In the kneading method, vanadium oxide or tungsten oxide (and / or the meaning, hereinafter the same) is mixed with a raw material which is converted into an oxide upon firing.
For example, hydroxides, halides, ammonium salts, sulfates and the like of these metals may be mixed.

In the case of the impregnation method, vanadium oxide or tungsten oxide is supported on a titanium oxide carrier (powder, granular, plate, rod, honeycomb, etc.). When the titanium oxide is a powder or a slurry, it is mixed with a solution of a vanadium salt or a tungsten salt to impregnate the active metal component.
When the titanium oxide is a molded body, the titanium oxide is directly poured into a solution of a vanadium salt or a tungsten salt to impregnate the active ingredient. When vanadium oxide and tungsten oxide are used, a method of supporting tungsten oxide on titanium oxide, finally supporting vanadium oxide, supporting titanium oxide on vanadium oxide, and then supporting tungsten oxide on titanium oxide when using vanadium oxide and tungsten oxide. Or a method in which titanium oxide is simultaneously impregnated with vanadium oxide and tungsten oxide. As a starting material for vanadium, for example, an aqueous solution of oxalic acid of ammonium metavanadate or an aqueous solution of vanadyl sulfate is used. For example, an aqueous solution of ammonium tungstate is used as a starting material for tungsten.

In the case of the coprecipitation method, an aqueous solution of a water-soluble titanium compound (for example, tetrachlorotitanium) and a water-soluble vanadium compound (for example, vanadyl sulfate) or a water-soluble tungsten compound (for example, ammonium tungstate) is prepared. A precipitate is obtained while preparing a suitable solution so that the pH is near neutral, and taking care not to generate excessive heat. The precipitate is filtered, washed (washed with water), dried and calcined to obtain a catalyst. In this way V
Alternatively, the other active metal can be supported by another method.

[0022]

The present invention will be described below in more detail with reference to examples. Example 1 N-2-aminoethyl-3 as a silane coupling agent
38 g of aminopropyltrimethoxysilane are dissolved in 200 ml of ethanol to form a solution, and the solution has an average particle size of 90 n.
88 g of titanium oxide particles were added, and the mixture was stirred at room temperature for 3 hours, and then ethanol was removed at 80 ° C. to obtain titanium oxide particles coated with a silane coupling agent. An aqueous vanadium sulfate solution (28.6 g / 100 ml) was added to the titanium oxide particles.
Was added, and a predetermined molding aid shown in Table 1 was further added. After kneading, extrusion molding was performed to obtain a honeycomb or cylindrical catalyst molded body. This was calcined at 300 to 600 ° C. (preferably 450 ° C.) in the atmosphere (or in an oxygen-added atmosphere) to obtain a catalyst. Table 2 shows the physical properties of the produced catalyst. Table 9 shows the composition of the catalyst used in the comparative example.

The evaluation of the obtained catalyst was performed as follows. The catalyst is packed in a fixed-bed microreactor, the reaction temperature is 200 ° C., and the W / F is 0.017 (g / min / m 2).
l), the test gas is the indicator organic halogen compound 300ppm,
An evaluation test of the catalyst with respect to the decomposition of the organic halogen compound was performed with an oxygen concentration of 10% and a nitrogen balance. As the indicator organic halogen compound, o-chlorophenol which is an alternative indicator substance for dioxins was used. The specific surface area of the catalyst was measured by a multipoint BET method using nitrogen adsorption.

The results are shown in Table 3. Here, K / Ko is an index of the catalytic activity in comparison with the case of the comparative example (Ko). As is clear from Table 3, it was confirmed that the catalyst of the present invention had higher performance than the catalyst of the comparative example. Example 2 In Example 1, N-2 was used as a silane coupling agent.
Titanium oxide particles coated with a silane coupling agent were obtained in the same manner except that a solution of 39.1 g of -aminoethyl-3-aminopropyltrimethoxysilane dissolved in 100 ml of ethanol was used. Next, a catalyst of the present invention was prepared in the same manner as in Example 1 except that an aqueous solution of titanyl sulfate (15.6 g / 100 ml of distilled water) was used in addition to the aqueous solution of vanadium sulfate (19.1 g / 100 ml of distilled water). did. Table 4 shows the physical properties and evaluation results of the obtained catalyst.
And 5. Example 3

In Example 2, a solution prepared by dissolving 80 g of N-2-aminoethyl-3-aminopropyltrimethoxysilane as a silane coupling agent in 200 ml of distilled water was used, and 76 g of silica particles were added thereto. Silica particles coated with the agent were mixed with vanadium sulfate (38.5 g / 100 ml distilled water) and titanyl sulfate aqueous solution (31.2 g / 100 ml distilled water),
A catalyst of the present invention was prepared in the same manner except that the molding aid shown in Table 6 was added and molded. The physical properties and evaluation results of the obtained catalyst are shown in Tables 7 and 8, respectively.

As a result of the evaluation, it was confirmed that the catalyst had high performance as shown in Table 7 as compared with the catalyst of the comparative example. Comparative Examples 1-3 Ammonium vanadate is added to the oxalic acid solution. Ammonium metavanadate is added according to the amount supported in each example. The amounts are shown in Table 9. To this, a raw titanium oxide powder is added, a predetermined molding aid is added, and after kneading and extrusion molding, a honeycomb or cylindrical catalyst molded body is obtained. This was calcined at 500 ° C. to obtain a catalyst. The obtained catalyst was evaluated in the same manner as in the example, and the results were shown in Table 3,
5 and 8 respectively.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

[Table 5]

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

[Table 8]

[0035]

[Table 9]

According to the present invention, when a catalytically active component is supported on titanium oxide particles, the catalyst component can be supported with high dispersibility by coexisting with an amino group-containing silane coupling agent. Thereby, higher catalyst performance than before can be obtained. In addition, by coexisting and supporting titanium ions at the same time as the catalyst component, the catalyst component and carrier component can be supported on oxide particles having a high specific surface area other than titanium oxide, and the catalyst performance can be dramatically improved. Becomes

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) B01J 37/08 B01D 53/36 ZABG (72) Inventor Masao Namba 3-1-1 Tamama, Tamano-shi, Okayama Prefecture Mitsui Engineering & Shipbuilding Co., Ltd. Tamano Works Co., Ltd. BB06A BC54B BD05A CA04 CA10 CA19 EA06 EA19 EB18X EC02Y EC10X FA02 FB04 FB06 FB34 FC04

Claims (5)

[Claims] 1. A method for producing a catalyst for purifying an organic chlorinated compound-containing gas, wherein a catalytically active component is supported on titanium oxide particles, wherein an amino group-containing silane coupling agent coexists when the catalytically active component is supported. A method for producing a catalyst for purifying a gas containing an organic chlorinated compound, comprising the steps of: 2. The method according to claim 1, wherein titanium ions coexist in addition to the silane coupling agent. 3. In addition to the titanium oxide particles, alumina
3. The method according to claim 1, wherein one or more particles selected from silica and a composite oxide thereof are used. 4. The obtained catalyst has at least three peaks in the pore size distribution, and the first peak has a peak of 300 nm to 450 nm.
4. The method according to claim 1, wherein the range of m, the second peak is in the range of 50 nm to 100 nm, and the third peak is in the range of 30 nm or less. 5. A material having a particle size of 5 nm to 60 as a titania raw material.
A titania particle of 0 nm is prepared, and a thermally decomposable substance having a particle size equal to or larger than a target pore size of the catalyst is kneaded as a porosifying agent, followed by firing to form a first peak of the pore size distribution. Organic pores having a pore size of not more than a pore formed as a gap between the titania particles, and adding a catalytically active component in the presence of an amino group-containing silane coupling agent at any stage during the preparation of the catalyst. A method for producing a gas purification catalyst containing a chlorinated compound.